It appears all really is fair in love and war for women - scientists say they are programmed to be critical of rivals when they are looking for a man.
Researchers at York University in Toronto, Canada, say women are prone to be at their cattiest when they are at their most fertile. They are more likely to criticise other women's appearance during the days around ovulation.
The aim is to attack rivals to boost their own chances of finding a mate. This extra-critical period may last for up to 10 days a month.
Dr Maryanne Fisher, who led the research, told BBC News Online: "When women are at their most fertile, they'll pay more attention to each other's appearance. "They are more likely to criticise, and to do it in a more pronounced way.
"There can be more catty behaviour, there will be more gossiping, nit-picking and spreading of nasty stories. "You might see two women in a pub and one might say to the other 'Oh God, look at her, she's so ugly' or 'your hair is such a mess'. "That is an example of a competitive strategy," reports &to=http://www.bbc.co.uk ' target=_blank>BBC
Science has proven what women have always known — they'll "dis" the competition to get the man they want. "Previously, women have been depicted as co-operative, kind-hearted and all of that. I think this adds to the small but growing body of research that says women are actually competitive," said Maryanne Fisher, the study's lead researcher and a doctoral candidate in psychology.
The researchers asked 104 male and female first-year York University psychology students to rate colour photographs of previous students' faces on a scale from one to seven, from extremely unattractive to extremely attractive. They were screened to eliminate mitigating factors such as sexual orientation and the use of oral contraceptives and anti-depressants. To gauge fertility, the women were asked to indicate where they were in their menstrual cycle. This study is only one step in uncovering women's mating techniques, Fisher said. "I think this is the tip of the iceberg. I think they do a lot more than this to attract men."
For example, women may put down other women's fidelity, promiscuity or maternal capabilities, the study says, informs &to=http://www.thestar.com' target=_blank>TheStar.com